When using replicated truncates, a special sampling strategy is used to sample the pre-image documents in the `config.system.preimages` collection. This sampling strategy cannot rely on the local or replicated size/count information for the collection, because at least on disaggregated storage, this size/count information is not available right now, and it will likely not be provided via replicated fast counts in the future, as `config.system.preimages` is an implicitly replicated collection.

As there is no usable size/count information for the collection available, the sampling makes up the size/count information. This made-up size/count information can be very inaccurate, which can affect the estimates for the number of documents contained in the collection truncate markers for `config.system.preimages`.
This potential inaccuracy will affect how much documents are reported as removed by the periodic change stream pre-images remover thread.

This change adjusts the log messages that report the number of documents removed, so that the log messages now indicate that the numbers are estimates and be inaccurate.